Loggerhead
Sea Turtle (Caretta caretta)

Photos
by J.D. Willson unless otherwise noted

Description:
The Loggerhead is a large sea turtle, with females typically more sizable than
males. An adult has a carapace length of 75- 112 cm (29.3-43.7 in) and weighs
77-159 kg (170-351 lb). Males are smaller but have longer tails than their female
counterparts; they often extend 30 cm (11.7 in) beyond the carapace. As can be
inferred from their nomenclature, these sea turtles have an abnormally large head-to-body
ratio. Their thick jaw, reddish brown color, and two claws on each flipper distinguish
this sea turtle from other species. In addition, the scutes do not overlap, and
the first costal scute is in contact with the nuchal scute. There are five or
more costals on each side of the carapace and three (usually) or four poreless
bridge scutes. Loggerheads also tend to sport more epibiota on their carapaces
then other sea turtles (more than 50 species of invertebrates have been found
associated with the Loggerheads shell). This may be due to their relatively
slow swimming speed.

Distribution and Habitat: While these sea turtles
can be found from the Canadian Maritime Provinces to Argentina, they nest for
the most part in temperate waters, and regularly north to the beaches of the Carolinas.
In the winter, they migrate to the southern Atlantic to avoid cold stunning (although
they can tolerate lower water temperature than most species of sea turtles). After
nest emergence, Loggerhead hatchlings perform a swimming frenzy for days in order
to reach the Sargasso Sea. When the small sea turtles are about 150 mm (5.9 in),
they make a transatlantic journey from the eastern Atlantic to the western Atlantic.
Their journey follows the Gulf Stream and the northern loop of the North Atlantic
Oceanic Gyre. At 41-46 cm (16-17.9 in) and possibly 6-10 years of age, they make
the return trip to the western Atlantic, remaining in shallow coastal waters for
the rest of their lives.

Reproduction and Development: Loggerhead
sea turtles nest in open sand dunes from May to October every 2-4 years. Many
females exhibit site fidelity, returning to the same beach where they were born
or where they nested previously. They lay an average of 115-125 eggs 4-6 times
per season at two-week intervals. Nests will incubate for an average of 55-65
days before hatchlings emerge. Warmer incubation temperatures produce more females,
while cooler incubation temperatures produce a higher number of males.

Habits:
Hatchling sea turtles will frequently feed on small invertebrates and fish eggs
found within their sargassum habitat. As they grow larger, their diet shifts to
include jellyfish and other invertebrates located near the surface. During their
final stage of development, these sea turtles become benthic feeders. Crabs and
mollusks make up the majority of the adult Loggerheads diet, although they
will also feed opportunistically on dead fish. Their powerful jaws can crush even
the sturdiest exoskeletons with ease. While fully-grown Loggerheads have few predators
(except for sharks and humans), eggs and hatchlings are susceptible to predation
from raccoons, hogs, ghost crabs, and fire ants, among others. Once they enter
the water, fish and seabirds prey upon hapless newborns.

Conservation:
Loggerhead sea turtles continue to be threatened by their most common predator,
humans, and are listed federally as an endangered species by the IUCN. Sea turtles
often drown at the hand of commercial fishing gear, especially shrimp trawls.
The advent of Turtle Excluder Devices (TEDs), which allow sea turtles to escape
from fishermens nets, have cut down on these losses. Another key issue is
habitat destruction and depredation. Notably, the placement of sea walls and jetties
causes permanent habitat loss for these animals. Lighting along beaches is an
obstruction to sea turtle conservation as it attracts nesting females and causes
disorientation in hatchlings.